A turbomachine annular combustion chamber comprises two coaxial revolution walls which extend one inside the other and which are connected together at their upstream ends by a chamber base annular wall, this chamber base wall comprising openings for mounting the aforementioned injection systems.
The injection systems include supply ducts which extend substantially radially from an external casing of the chamber, and heads aligned axially with the openings of the chamber base wall. The head of each injector is provided with an atomizing nozzle producing a fuel cone in the chamber, this fuel cone being intended to mix with air coming from a compressor of the turbomachine in order to form a pool of air and fuel, substantially tapered enlarging downstream.
The combustion chamber is provided with at least one or two spark plugs which are intended to start the combustion of the mixture of air and fuel in the chamber. Each spark plug is mounted in an orifice of the external revolution wall of the chamber and extends towards the axis of one of the injection systems, in order to ignite the pool produced by this injection system, the flame then propagating to the neighbouring pools produced by the other injection systems.
In altitude, the low pressures, the low temperatures and the variations in the viscosity of the fuel, have for effect to reduce the angle of opening of the pools, which can interfere with the relighting of the chamber in flight.
A known solution to this problem consists in deviating radially towards the exterior the pool produced by the injection system located as close as possible to the spark plug, in such a way as to bring this pool close to the spark plug and as such favour the relighting of the chamber in flight. However, this solution is not entirely satisfactory since it does not make it possible to improve the propagation of the flame to the other pools.